Page 18
3LINK SETUP

Before proceding further, it should be noted that another 3link setup spreadsheet can be found on Page 40. You might find the options on the Page 40 spreadsheet more desireable for your application.

This is something which is probably of more interest to the dragracer, but, since Jaguar used this on their early C-Types, I would urge those who are running a RWD beam axle car on road courses to consider this information.
 
This is an asymmetric trailing 3 link arrangement which, during forward acceleration, completely cancels driveshaft torque, thereby providing equal rear tire loading for maximum acceleration. There are 2 symmetrically situated links (in plan view) and a third "odd" link which is offset from the car's centerline (to the right). All links, in plan view, are assumed to be parallel to the long axis of the car (i.e., parallel to the SAE X-axis).

In the dragracing application, it is generally desirable to have the antisquat at or near 100%. In a road racing application, however, this high value of antisquat commonly causes wheel hop during braking. The spreadsheet allows the user to specify the percent antisquat. The default value is 100%.

Jaguar placed the odd link above the axle, but it can be either above or below. When placed below, the situation becomes more favorable with a "tubbed" car. The drawback is that the single lower link is carrying a very large compressive load. Care should be taken to use tubing with sufficient wall thickness and diameter for safety.

It is assumed that the symmetrical links, in plan view, are arranged symmetrically about the car's centerline and that the center of gravity is on or near that same centerline. It should be noted, however, that the spreadsheet equations assume the odd link offset to be measured from the midpoint of the transverse spacing of the symmetrical links. In other words, it is not required that the "symmetrical" links be truly symmetrical. The two links, themselves, could be offset from the car's centerline. If the link pair were offset, say, 2 inches to the left of the car's centerline and the odd link 4 inches to the right of the car's centerline, the true odd link offset would be 6 inches and it is this number that should be inserted in the spreadsheet. This might be considered if a packaging problem exists.

length of odd link =

left & right link lengths =

offset of odd link =

effective rear tire radius =

axle ratio =

weight of car with driver =

weight of rear axle assembly =

center of gravity height =

wheelbase =

lateral spacing between left & right links =

desired % antisquat =

ODD LINK REAR MOUNTING POINT

distance forward from rear axle centerline =

vertical distance from track surface =

LEFT AND RIGHT SIDE REAR MOUNTING POINTS

distance forward from rear axle centerline =

vertical distance from track surface =

ANSWERS:

VERTICAL DISTANCES FROM SHOP FLOOR TO FRONT OF LINK
"Odd" Link Left And Right Links

INSTANT CENTER HEIGHT

LINK LOADS AT 1G ACCELERATION
Left Link
Right Link
Odd Link
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